By default, no logs are enabled, except the error log on Windows.
(The DDL log is always created when required, and has no
user-configurable options; see Section 5.4.6, “The DDL Log”.) The
following log-specific sections provide information about the server
options that enable logging.

The relay log is used only on slave replication servers, to hold
data changes from the master server that must also be made on the
slave. For discussion of relay log contents and configuration, see
Section 16.2.4.1, “The Slave Relay Log”.